The present disclosure relates to hemostats or forceps used for open surgical procedures and laparoscopic surgical procedures. More particularly, the present disclosure relates to a multi-pronged bipolar forceps which allows a user to selectively seal, cauterize, coagulate/desiccate and/or cut vessels and vascular tissue at multiple sites without manipulating the forceps.
1. Technical Field
A hemostat or forceps is a simple plier-like tool which uses mechanical action between its jaws to constrict tissue and is commonly used in surgical procedures to grasp, dissect and/or clamp tissue. Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, cut and/or seal tissue.
By controlling the intensity, frequency and duration of the electrosurgical energy applied to the tissue, a surgeon can either cauterize, coagulate/desiccate and/or cut tissue and/or simply reduce or slow bleeding. Generally, the electrical configuration of electrosurgical forceps can be categorized in two classifications: 1) monopolar electrosurgical forceps; and 2) bipolar electrosurgical forceps.
Monopolar forceps utilize one active electrode associated with the clamping end effector and a remote patient return electrode or pad which is attached externally to the patient. When electrosurgical energy is applied, the energy travels from the active electrode, to the surgical site, through the patient and to the return electrode.
Bipolar electrosurgical forceps utilize two generally opposing electrodes which are disposed on the inner opposing surfaces of the end effectors and which are both electrically coupled to an electrosurgical generator. Each electrode is charged to a different electric potential. Since tissue is a conductor of electrical energy, when the effectors are utilized to clamp or grasp tissue therebetween, the electrical energy can be selectively transferred through the tissue.
The process of coagulating small vessels is fundamentally different from vessel sealing. For the purposes herein the term coagulation is defined as a process of desiccating tissue wherein the tissue cells are ruptured and dried. Vessel sealing is defined as the process of liquefying the collagen in the tissue so that it cross-links and reforms into a fused mass. Thus, coagulation of small vessels is sufficient to close them, however, larger vessels need to be sealed to assure permanent closure.
In order to effect a proper seal with larger vessels, two predominant mechanical parameters must be accurately controlled--the pressure applied to the vessel and the gap between the electrodes both of which affect thickness of the sealed vessel. More particularly, accurate application of the pressure is important to oppose the walls of the vessel, to reduce the tissue impedance to a low enough value that allows enough electrosurgical energy through the tissue, to overcome the forces of expansion during tissue heating and to contribute to the end tissue thickness which is an indication of a good seal. In some instances a fused vessel wall is optimum between 0.015 and 0.060 millimeters (0.006 to 0.020 inches).
As mentioned above, electrosurgical energy may be applied through the tissue to halt or prevent bleeding. Traditionally, forceps are used to create a single seal per application of electrosurgical energy. Additional seals are made by moving/manipulating the forceps to a second sealing site and applying more electrosurgical energy. For example, when vessels need to be sealed and cut, a surgeon typically makes two seals and cuts between the seals or the surgeon makes three seals and cuts along the centerline of the middle seal. To make these two or three seals, the surgeon manipulates the forceps two or three times and applies electrosurgical energy after each manipulation. This process can be time consuming especially when cutting multiple vessels.
Numerous bipolar electrosurgical forceps have been proposed in the past for various surgical procedures. However, none of these forceps are designed to seal vessels at multiple sealing sites without manipulating the forceps. For example: U.S. Pat. Nos. 2,176,479 to Willis; 4,005,714 to Hiltebrandt; 4,370,980, 4,552,143, 5,026,370 and 5,116,332 to Lottick; 5,443,463 to Stern et al.; 5,702,390 to Austin et al.; and 5,484,436 to Eggers et al., all relate to electrosurgical instruments for coagulating, cutting and/or sealing vessels or tissue.
Stern et al. relates to a coagulating device which utilizes a series of electrodes disposed on an inner facing surface of one end effector with a corresponding pair of temperature sensors disposed on the opposite end effector for sensing the temperature rise in the tissue and providing feedback to an electrosurgical generator to control the rate of coagulation of the tissue.
Austin relates to a bipolar instrument which utilizes a triangularly-shaped electrode pivotally disposed between two parallel electrodes. The triangularly-shaped electrode can be positioned such that in the closed configuration the base of the triangle coagulates tissue between the two parallel electrodes or the triangularly-shaped electrode can be positioned such that in the closed configuration the triangle apex cuts tissue between the two parallel electrodes.
Thus, there exists a need to develop a bipolar forceps which can effectively seal, cauterize, coagulate and/or cut vessels and tissue at multiple tissue sites without manipulating the forceps.